• Journal of Microbiology
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• v.42 no.1
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• pp.51-55
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• 2004

The influence of feedstock amino acids, salt, carbon and nitrogen sources on glutathione production by Saccharomyces cerevisiae FF -8 was investigated. Glucose, yeast extract, KH$_2$PO$_4$, and L-cysteine were found to be suitable feedstock. Highest glutathione production was obtained after cultivation with shaking for 72 h in a medium containing glucose 3.0% (w/v), yeast extract 3.0%, KH$_2$PO$_4$ 0.06% and L-cysteine 0.06%. The glutathione concentration achieved using this medium increased 2.27-fold to 204 mg/l compared to YM basal medium.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.05a
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• pp.90-95
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• 1997

In this work, linear dynamics of a circulating fluid-fueled subcritical reactor system with temperature feedback and external neutron source was modeled and examined. In a circulating fluid-fuel system, the stable region is slightly moved by a circulation fluid effect. The effects of subcriticality and temperature feedback coefficient on the reactor stability were tested by calculating frequency response of neutron density originated from reactivity perturbation or external source oscillation of system. The amplitude transfer function has a different shape near subcritical region due to the exponential term in the transfer function. The results of the study show that at a slightly subcritical region, low frequency oscillation in accelerator current or reactivity can be amplified depending on the temperature feedback. However, as the subcriticality increases, the oscillation becomes negligible regardless of the magnitude of the temperature feedback coefficient.

• 한국신재생에너지학회:학술대회논문집
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• 2005.11a
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• pp.92-101
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• 2005

세계적으로 수소에너지를 미래 에너지의 대안으로 여겨지고 있기 때문에 수소에너지 관련기술은 미래 국가 경쟁력을 좌우할 것으로 예상되고 있으며 수소에너지시대의 핵심인 수소스테이션 관련기술을 개발은 국가 연료전지 시장을 비롯한 수소 자동차 산업 전반에 큰 영향을 미칠 것으로 예상되고 있다. 이에 따라 전 세계적으로 수소에너지를 차세대 에너지원으로 개발하기 위하여 전력을 다하고 있으며 수소제조기술개발 및 수소스테이션 실증연구가 진행되고 있다. 본 연구에서는 수소제조장치 관련 국내외 기술개발 현황과 수소스테이션용 고효율 수소제조장치 장치 개발 현황을 소개하고자 한다.

• Korean Journal of Acupuncture
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• v.28 no.3
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• pp.165-175
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• 2011

Objectives : The purpose of this study is to review and summarize the research on Polycystic ovarian syndrome (PCOS). Methods : We searched the clinical studies with keywords of Polycystic ovarian syndrome and acupuncture therapy through the search site called CAJ (china academic journal) from 2000 to 2011. Results and Conclusions : We reviewed 22 studies about PCOS which were relative to acupuncture therapy. We investigated the frequency of Acupuncture point for PCOS in this article exclusive Auricular acupuncture treatment. SP6 (Sam$\={u}$mgyo), CV4 (Kwanwon), CA111 (Chagung), SP10 (Hy$\={o}$lhae), CV6 (Kihae), B23 (Shinsu) and S40 (P'ungnyung) were used frequently. Acupuncture therapy was effective method to improve Polycystic ovarian syndrome. Further studies needed for Polycystic ovarian syndrome.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.12
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• pp.198-203
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• 1999

In this study, chip-tool friction and shear characteristics of cold drawn free machining steels in turning were assessed. To do this, a newly developed equivalent oblique cutting model was adopted. And for comparison with those of free machining steels, chip-tool friction and shear characteristics of conventional carbon steels were also investigated. The Pb-S free machining steel shows superior machinability to others. In case of the Bi-S free machining steel, the shear stress and the specific friction energy are relatively lower than those of conventional carbon steels, but its shear strain is relatively high, so it does not show any remarkable improvement of machinability.

• Nuclear Engineering and Technology
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• v.38 no.5
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• pp.423-426
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• 2006

A developed neutron activation analysis(NAA) and gamma-spectrometry were applied to improve the analytical sensitivity and precision of impurities in electronic-circuit raw materials. It is well known that soft errors in high precision electronic circuits can be induced by alpha particles emitted from naturally occurring radioactive impurities such as U and Th. As electronic circuits have recently become smaller in dimension and higher in density, these alpha-particle emitting radioactive impurities must be strictly controlled. Therefore, new NAA methods have been established using a HTS(Hydraulic Transfer System) irradiation facility and a background reduction method. For eliminating or stabilizing fluctuated background caused by Rn-222 and its progeny nuclides in air, a nitrogen purging system is used. Using the developed NAA and gamma-spectrometry, ultra trace amounts of U(0.1ng/g) and Th(0.01ng/g) in an alumina ball and high purity silica used for an epoxy molding compound (EMC) could be determined.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.2212-2212
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• 2011

현재 국내의 경우 설비의 열화 상태 및 그 경향을 파악하여 부적합한 상태를 파악하기 위한 다양한 상태판단 기술이 개발되고 있다. 본 논문에서는 전기철도 DC 전력설비 과부하 상태판단 기술과 설계 방향에 관하여 기술하였다. 또한 실용적 리뉴얼 방향과 실용적교체 기준의 국내외 기법을 조하하여 이를 적용하기 위한 기술연구를 수행하였으며 이를 바탕으로 도시철도 전력설비의 실태진단을 위한 노후화 시스템 교체 기준 수립의 기초 연구 및 기본 조사 방향이 되고자 하였다.

• Proceedings of the KAIS Fall Conference
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• 2010.11a
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• pp.168-171
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• 2010

본 논문에서는 GaN HEMT 소자를 이용한 고출력 고효율 특성을 가지는 광대역 SSPA의 개발을 다루고 있다. 개발한 SSPA는 8W 급과 15W 급의 GaN HEMT 소자를 사용하여 Pre-Drive 증폭단을 구성하였으며, Drive 증폭단은 50W/150W급 GaN HEMT 소자를 직/병렬구조로 사용하였다. Main 증폭단은 4-way 분배기와 결합기를 이용한 Balanced Structure를 적용하여 높은 출력을 구현하였으며, 안정적인 동작을 위하여 음(-)전원 제어 회로와 출력신호 검출 회로를 포함하고 있다. 제작된 SSPA의 사용가능 대역은 2.9GHz~3.3GHz로 단일전원을 사용하고 있으며 100us 펄스 폭, 10% Duty Cycle 조건에서 60dB의 전압이득, 1kW 출력과 약 28% 효율 특성을 가지는 것으로 측정되었다. 본 논문에서 개발한 SSPA는 S-대역을 사용하는 레이더시스템의 송신단에 적용될 수 있다.

• Journal of Korean Society for Quality Management
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• v.22 no.1
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• pp.54-65
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• 1994

Multivariate exponentially weighted moving average (EWMA) control charts for monitoring the variance-covariance matrix are investigated. Two basic approaches, "combine-accumulate" approach and "accumulate-combine" approach, for using past sample information in the developement of multivariate EWMA control charts are considered. Multivariate EWMA control charts for monitoring the variance-covariance matrix are compared on the basis of their average run length (ARL) performances. The numerical results show that multivariate EWMA control charts based on the accumulate-combine approach are more efficient than corresponding multivariate EWMA control charts based on the combine-accumulate approach.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.3 no.1
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• pp.13-18
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• 2010

In this study, heart rate through ECG R-R intervals using the methods about how to automatically extract studied. Heart rate as measured by the naked eye, using the 2-order differential equations to extract heart rate, using self-correlation function to extract the heart rate was compared contemplate. To verify its efficacy and validity in practical applications, these method has been applied to MIT/BIH database. Based on this, making a ECG meter automatic heart rate measurements, and our ECG meter was compared with the existing ICU.